1. Field of the Invention
This invention relates generally to acoustic hearing protective devices and, more particularly, to an acoustical earmuff device having a pair of earmuff cup assemblies, each assembly including a rigid cup, wherein at least a portion of the rigid cup is transparent or translucent so that an earplug inserted within a wearer's ear is visually perceivable from the outside of the rigid cup.
2. Brief Discussion of the Prior Art
Environmental sounds are typically comprised of a mixture of various sound wave frequencies having varying intensities. It is well documented that repeated or prolonged exposure to sounds of sufficiently high sound pressure level will cause temporary or permanent hearing loss. For example, exposure to sound waves of some frequencies and of varying intensities under prolonged exposure can damage the auditory organ and cause serious hearing problems, including deafness. Injurious noises such as those caused by explosions or bursts are often comprised of a mixture of sound wave frequencies of varying intensity. These disturbing frequencies are in both the high and low frequency bands and have an intensity sufficient to cause hearing problems. Individuals who are frequently exposed to sound having such disturbing and sometimes dangerous frequencies and intensities run the risk of incurring such injuries as hearing loss or even deafness. These individuals include workers at demolition or construction sites, operators of heavy, noisy equipment and those in active military service. Ear (i.e. hearing) protection is needed to prevent a loss in hearing acuity and the gradual increase in the threshold of hearing resulting from extended exposures to loud noise.
Sound attenuation devices arc known which specifically address this problem. These include conventional earplugs, earmuffs, and the like which function to reduce the negative effects of exposure to dangerous frequencies by limiting the entry of all sound waves into the auditory organ. In environments where very high noise levels exist, dual hearing protection is often required. This results because if the attenuation that can be provided by a single hearing protective device is inadequate for a given noise exposure and if noise control procedures are impracticable, the one viable alternative is to use dual hearing protection. One example of dual hearing protection is an earplug used in combination with an earmuff assembly. The attenuation of the combination of these two devices is better than attenuation of either device alone and thus, dual hearing protection offers additional protection when the user is exposed to a high noise level environment.
One of the associated disadvantages of a dual hearing protective device is that people generally do not like to put objects into their ears and wear them for periods of time. For this reason and others, dual hearing protection wearers often wear the earmuff without having the pair of earplugs inserted into the ears. Consequently, the advantages offered by the dual hearing protective device are not realized and the wearer is exposed to greater levels of noise and greater risks. A wearer can wear only the earmuff without the earplugs because conventional earmuffs do not allow a supervisor or other hearing conservationist to easily enforce the use of both hearing protective devices since these individuals cannot see the earplug within each ear when the earmuff is in place surrounding the user's ears. A conventional set of acoustical earmuffs typically includes a pair of earmuff cup assemblies connected by a suitable means to a flexible headband. Each earmuff cup assembly generally consists of a rigid cup, a cushion, and optionally a sound absorbing liner. The rigid cup is formed of suitable materials and generally is formed of a relatively stiff material such as rigid polyvinyl chloride, acrylonitrile butadiene styrene (ABS) or the like. The rigid cup of the prior art are opaque in nature and thus prevent the passage of light rays through the cup material.
Accordingly, it has been found to be very difficult to enforce the use of dual hearing protection without having spot checks where the wearer is asked to remove the earmuff so that the supervisor or hearing conservationist can directly observe whether the pair of earplugs are inserted into the wearer's ears. When an individual is subjected to a spot check, the individual must discontinue working and thus productivity is lost due to the spot check. As the number of spot checks and the number of persons subjected to them increases, productivity will continue to decrease resulting in lower profitability and increasing production times. In addition, the wearer will need to at least partially remove the earmuff resulting in the wearer's ears being exposed to potentially damaging sounds. This greatly increases the chances of injury or damage to the ears. As a result, there is a need for a method and dual hearing protective device which permits the supervisor or another individual to determine whether the wearer is complying with rules, regulations, and the like by wearing the dual hearing protective device.